Systems and methods for pipe couplings

ABSTRACT

A coupling arrangement that includes a gasket seal and a housing having a first lateral side for receiving a first pipe segment and a second lateral side for receiving a second pipe segment, the second lateral side being spaced from the first lateral side to define a medial axis of the housing. An inner surface of the housing defines a cavity for engaging and housing a gasket seal disposed about the first and second pipe segments. The gasket seal includes a peripheral surface and inner surface which can include features than engage both the housing and the pipe segments to form a fluid tight pipe joint assembly.

PRIORITY DATA & INCORPORATION BY REFERENCE

This is a continuation application of U.S. patent application Ser. No.13/504,097, filed Jun. 21, 2012, which is an application under 35 U.S.C.§ 371 of International Application No. PCT/US2010/053970 filed Oct. 25,2010, which claims the benefit of priority to U.S. Provisional PatentApplication No. 61/255,409, filed Oct. 27, 2009, entitled “Systems andMethods for Pipe Couplings”, the entirety of each is incorporated byreference herein.

TECHNICAL FIELD

This invention relates generally to pipe fittings and more specificallydevices and methods for coupling fluid conveying piping or tubing.

SUMMARY OF THE INVENTION

Provided are preferred coupling arrangements and their components forjoining pipe or tube segments. In one preferred embodiment, a couplingis provided that includes a housing; and a gasket disposed in thehousing for forming a seal about a pipe joint. The gasket is an annularor ring-type body having a first lateral side and a second lateral sidespaced from the first lateral side so as to define a medial axistherebetween. An exterior or peripheral surface of the gasket and aninner surface of the gasket extend between the first and second lateralsurfaces so as to be bisected by the medial axis. The inner surfacepreferably defines a first sealing lip and a second sealing lip. Thefirst and second sealing lips are preferably disposed about the medialaxis so as to define a first transition portion of the inner surfaceextending between the first sealing lip and the medial axis and a secondtransition portion between the second sealing lip and the medial axis.The first and second transition portions extend in the direction fromthe sealing lip towards the medial axis and the peripheral wall so eachpreferably defines a positive slope. More preferably, the inner surfaceof the gasket defines a central leg extending along the medial axis.Moreover, the transition portions provide for a decreases in thethickness of the gasket body in direction from the lateral sides to themedial axis or central leg.

Another preferred gasket is provided which includes a first lateralside, a second lateral side spaced from the first lateral side so as todefine a medial axis therebetween. The gasket includes a peripheralsurface and an inner surface, each of which extend between the first andsecond lateral surfaces so as to be bisected by the medial axis. Theperipheral surface preferably defines a profile having a pair ofradiused end portion disposed about the medial axis with a centralportion extending between the two radiused end portions, the radiusedend portions defining the maximum diameter of the gasket. In oneembodiment, the central portion defines an arcuate profile thatintersects the medial axis. Alternatively, the central portion profileis substantially linear. In another preferred embodiment, the innersurface of the gasket defines a first sealing lip and a second sealinglip, the first and second sealing lips being disposed about the medialaxis, the inner surface including a transition portion extending in thedirection from one of the first and second sealing lips towards themedial axis and the peripheral wall so as to define a positive slope.

A preferred housing for use in a preferred coupling arrangement includesa first lateral side for receiving a first pipe segment and a secondlateral side for receiving a second pipe segment. The second lateralside is spaced from the first lateral side to define a medial axis ofthe housing. The housing includes an inner surface defining a cavity forengaging the gasket and extends between the first lateral side and thesecond lateral side so as to define an inner diameter profile whichdecreases in a direction from the lateral side to the medial axis todefine a point of contact diameter that engages the gasket. A preferredgasket disposed in the cavity of the housing has a diameter that isgreater than the point of contact diameter. In one preferred embodiment,the inner surface defines a medial diameter of the housing which is nogreater than the point of contact diameter.

In one preferred embodiment of the housing, the inner surface includes asidewall portion; a backwall portion; and a transition portion betweenthe sidewall portion and the backwall portion. The transition portionpreferably defines a negative slope in the direction from the onelateral side to the medial axis and includes a first radiused portion, asecond radiused portion with a straight line segment extending betweenthe first and second radiused portions. The straight line segmentdefining the preferred negative slope.

A preferred method of sealing a pipe joint is provided and includesradially compressing a tapered inner surface of a housing component on agasket disposed within a cavity defined by the inner surface. The gaskethas a medial axis, a flex point, and a linear segment between the flexpoint and the medial axis. The linear segment preferably defines apositive slope in the direction toward the medial axis. The preferredmethod further includes locating a notch defined by the tapered surfacebetween the medial axis and the flex point a lower point such that thecompressing moves a lateral portion of the gasket against a sidewall ofthe housing.

Another preferred coupling includes a gasket and a housing having afirst lateral side and a second lateral side spaced from the firstlateral side to define a medial axis of the housing. The housingincludes an inner surface which defines a cavity for engaging the gasketand extends between the first lateral side and the second lateral sideso as to define an inner diameter profile which decreases for at least aportion between at least one of the lateral sides and the medial axis.The inner surface includes a sidewall portion, a backwall portion, and atransition portion between the sidewall portion and the back wallportion. The transition portion preferably defines a negative slope inthe direction from the one lateral side to the medial axis, and includesa first radiused portion, a second radiused portion with a straight linesegment extending between the first and second radiused portions. Thestraight line segment defines the negative slope with the first radiusedportion having a center of curvature disposed on one side of thestraight line, the second radiused portion having a center of curvaturedisposed on the other side of the straight line, the first radiusedportion defining a first cavity depth of the housing and the secondradiused portion defining a second cavity depth less than the firstcavity depth, the backwall portion defining a third cavity depth beingequal to the second cavity depth. A preferred gasket includes a firstlateral side and a second lateral side spaced from the first lateralside so as to define a gasket medial axis. The preferred gasket furtherincludes an exterior surface and an inner surface, which extends betweenthe first and second lateral surfaces so as to be bisected by the medialaxis. The inner surface defines a first sealing lip and a second sealinglip, the first and second sealing lips being disposed about the medialaxis. The inner surface includes a transition portion extending in thedirection from the sealing lip towards the medial axis and theperipheral wall so as to preferably define positive slope. The exteriorsurface defines a profile including a pair of enlarged end portionsdisposed about the gasket medial axis of the gasket with a centralportion disposed therebetween. The central portion is preferablyradially inward of the enlarged end portions to engage the backwallportion of the housing.

BRIEF DESCRIPTIONS OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and constitutepart of this specification, illustrate exemplary embodiments of theinvention, and, together with the description given above, serve toexplain the features of the invention,

FIG. 1A is a perspective schematic of a preferred coupling arrangement.

FIG. 1B is an end view of the coupling arrangement of FIG. 1A.

FIG. 2A is a perspective schematic of another preferred couplingarrangement.

FIG. 2B is an end view of the coupling arrangement of FIG. 2A.

FIG. 3A is a partial cross-sectional view of a preferred couplingarrangement in an uncompressed configuration.

FIG. 3B is the coupling arrangement of FIG. 3A in a compressedconfiguration.

FIG. 4A is a preferred housing component for use in the arrangements ofFIGS. 1A-1B and FIG. 2A-2B.

FIG. 4B is another preferred housing component for use in thearrangements of FIGS. 1A-1B. and FIG. 2A-2B.

FIG. 5A is a preferred gasket for use with the housing component FIG.4A.

FIG. 5B is a preferred gasket for use with the housing component FIG.4B.

FIG. 5C is another preferred gasket for use with the arrangement ofFIGS. 3A-3B.

FIG. 6A is a partial cross-sectional view of another embodiment of acoupling arrangement.

FIG. 6B is a partial cross-sectional view of another embodiment of acoupling arrangement.

DETAILED DESCRIPTION

Shown in FIGS. 1A and 1B and FIGS. 2A and 2B, is the formation of apreferred pipe or tube joint assembly using a preferred couplingarrangement 10. In the preferred joint assembly, the pipe or tube endsegments 2, 4 are axially aligned along a pipe axis X-X and a gasket 40is disposed about the end segments 2, 4. The pipe or tubing may becopper, steel or other tubular material for forming a joint assembly. Apreferred coupling housing having at least two housing components 12, 14are engaged about the gasket 40. The housing components may be separatecomponents as seen in FIG. 1A or alternatively may be pre-assembled in acoupled arrangement, for example in the hinge-type arrangement shown inFIGS. 2A and 2B. One preferred hinged coupling for use in the couplingarrangement is shown and described in U.S. Provisional Application No.61/255,351, filed on Oct. 27, 2009, entitled, “Systems and Methods forHinge Couplings,” and which is incorporated by reference in itsentirety. The housing components may be identical in structure so as tomirror one another about X-X or alternatively may be configureddifferently, so long as they are configured to engage or align with oneanother and form the complete coupling housing about the gasket 40.Moreover the coupling housing can be formed by more than two componentsprovided the components can be coupled together to effectively engagethe gasket 40 to form the pipe joint as seen, for example, in U.S. Pat.No. 6,139,069 which is incorporated by reference in its entirety.

Generally, each of the housing components 12, 14 have a first end 16, asecond end 18 with a preferably arcuate segment 20 extending between thefirst and second ends 16, 18 for engagement with the gasket 40.Depending on the number of components forming the housing, the segmentscan be semi-circular, quarter-circle or define another arc-length. Theends 16, 18 are preferably configured as bolt pad extensions havingthrough holes in which fasteners 19 are disposed to secure and/or couplethe housing components 12, 14 to one another. The pipe engaging segments20 further include an inner surface 22 that defines a gasket cavity 24for engaging and housing the gasket 40.

In order to complete the formation of the pipe joint, the housingcomponents 12, 14 are disposed over the gasket 40. To form the fluidtight seal, the fasteners are tightened so as to draw the housings 12,14 together. As the components 12, 14 are drawn together, the innersurface 22 of the components compress the gasket 40 to form a fluidtight seal. The completed assembly defines the central axis C-C of thecoupling arrangement 10, which is co-axially aligned with the pipe axisX-X.

Respectively shown in FIG. 3A and FIG. 3B are uncompressed andcompressed views of the preferred pipe joint assembly to illustrate thesurface contact engagement between the inner surface 22 of the housingcomponent 12 and the gasket 40. Preferably, the coupling arrangement 10is symmetrical about a medial axis A-A that extends perpendicularly tothe central axis C-C of the coupling 10. Alternatively, the arrangementcan be asymmetrical, for example, as is the case of a reduced pipe jointarrangement. The preferred housing 12 and its inner surface 22 define apreferred surface profile 106. The surface profile 106 preferablyincludes a portion that tapers inwardly toward the medial axis A-A todefine a decreasing inner diameter and form one or more notches 30disposed about the medial axis A-A. Notches 30 can alternatively bedefined by triangles formed on the inner surface 22 about medial axisA-A in which the vertices extend radially inward into the cavity 24.Referring to the compressed view of FIG. 3B, the inner surface 22 andits profile 106 engage the peripheral surface of the gasket 40 applyinga radial compressive force. The notch 30 and its tapering surfaceinclude a point P0 that defines an interior diameter of the innertapering surface 22 that is smaller than the diameter of the gasket 40at the location where the point P0 makes contact. Accordingly, informing a fluid tight seal in the pipe joint with the couplingarrangement 10, the notch 30 deforms the gasket 40 at the point P0 ofcontact preferably radially toward the axis C-C. Due to an interiorchannel 58 of the gasket 40, the lateral portion of the gasket 40 foldsat a point P1 along the profile of the channel 58 to form the sealedengagement with the outer surface of the pipe segment 2, 4 and thelateral portion of the gasket 40 moves laterally against the innersurface 22 of the housing 12. Internal fluid pressure in the pipe jointcan move a central portion of the gasket 40 radially outward to contactthe inner surface 22 of the housing at the deepest part of the gasketcavity 24 to further stabilize the position of the gasket 40 within thecavity 24. For the preferred coupling arrangement 10, the formation ofthe notch 30 preferably locates the contact point P0 medially inward ofthe flex point P1 of the gasket relative to the medial axis A-A suchthat the contact point P0 is medial of the flex point P1. Moreover, thepoint P0 is preferably located so as not to minimize or negate theability of the internal fluid pressure to move the gasket radiallyoutward against the coupling housing.

FIG. 3A shows a cross-sectional general view of the preferred housingcomponent 12 having a first lateral side 100 and a second lateral side102 which define therebetween the medial axis A-A of the housingcomponent 12. Extending between the first and second lateral sides isthe body of the component 12 which includes a peripheral surface profile104 (seen in FIGS. 4A and 4B as 104′ and 104″) and a preferred innersurface profile 106 of the inner surface 22. The inner surface 106preferably includes to each side of the medial axis A-A, a pipeengagement portion 108 (shown in FIGS. 4A and 4B as 108′ and 108″), asidewall portion 110, a backwall portion 112, and a transition portion114 extending between the sidewall and backwall portions 110, 112. Thepipe engagement portion 108 directly engages the outer surface of thepipe segment in the pipe joint assembly and preferably extendssubstantially linearly parallel to the central axis C-C of the couplingarrangement 10. The sidewall portion 110 is contiguous with the pipeengagement portion 108 to define a surface for engagement with thesidewall of the gasket 40 in the joint assembly. The sidewall portion110 is also preferably substantially linear defining a preferably obtuseangle α with line parallel to the medial axis A-A. More preferablyformed between the pipe engagement portion 108 and the sidewall portion110 is a surface transition 109, which can either be radiused defining aradius of curvature or more preferably defines a step transition betweenthe pipe engagement portion 108 and the sidewall portion 110.

The backwall portion 112 of the inner surface profile 106 preferablydefines the portion of the housing inner surface 22 which supports amedial portion of the gasket 40 and more preferably define the deepestportion of the gasket cavity 24. Alternatively, backwall 112 can belocated at a depth equivalent to the contact point P0 of the notch 30,or at a depth shallower than P0 but deeper than point P1 of the gasket.In the preferred embodiment 12, the back wall portion 112 of the innersurface 106 profile is substantially linear or planar extending in adirection parallel to the central axis C-C of the coupling 10.Alternatively, the backwall portion 112 can be a single deepest point ofcontact of the inner surface 104 for engagement with the gasket 40.Further in the alternative, the backwall portion 112 can define asegment of the inner surface 106 that defines multiple points of contactfor the gasket 40, in which the multiple points of contact define thedeepest point of the gasket cavity which engage the gasket 40.

Contiguously extending between the backwall portion 112 and the sidewallportion 110 of the inner surface profile 106 is the transition portion114. The transition portion 114 preferably includes a first radiused end114 a which defines a radius of curvature contiguous with the sidewallportion 110, and a second radiused end 114 b which defines a radius ofcurvature contiguous with the backwall portion 112. Alternatively theends 114 a, 114 b can be more of a step type transition. Between theends 114 a, 114 b the transition portion 114 preferably defines thenotch 30 of the inner surface 22 described above. Preferably, thetransition portion 114 defines a segment 114 c of the inner surfaceprofile 106 having a negative slope, meaning that in the direction froma lateral side 100, 102 to the medial axis A-A, the depth of the gasketcavity 24 decreases over the length of the sloping segment 14 c in thelateral to medial direction. Accordingly, the segment 114 c defines anarrowing taper of the inner surface profile 106 for the couplinghousing component 12 in the lateral to medial direction so as to definea decreasing inner diameter of the housing over the segment 114 c. Thesegment 114 c is preferably linear or alternatively may be defined by anundulating or other non-linear profile over its length provided thesegment defines a narrowing taper in an area of the inner surface 22 ofthe housing component 12 that contacts the gasket 40. The transitionportion 114 of the inner surface profile 106 can include a combinationof linear and nonlinear segments provided that the transition portion114 effectively defines a notch 30 as described above.

Shown in FIG. 4A is a preferred housing component 12′ for a preferrednominal six inch (6 in.) coupling 10′. The component has a first lateralside 100′ and a second lateral side 102′ spaced apart from one anotherto define the medial axis A′-A′ of the housing component 12′. Thelateral sides 100′, 102′ define the width W of the coupling 10′ aboutthe medial axis A′-A′ in which the width W preferably ranges from about1.5 to about three inches and is approximately 1.8 inches. The housingcomponent 12′ includes a peripheral surface 104′ which defines the outersurface of the coupling assembly 10′. The housing component 12′ furtherincludes an inner surface profile 106′ to define the gasket cavity 24′for housing a gasket 40. The preferred inner surface profile 106′ issymmetrical about the medial axis A′-A′ and includes at its lateral endthe pipe engaging surface 108′. Extending medially, the inner surfaceprofile 106′ further includes the sidewall portion 110′ with asubstantially step transition 109′ between the pipe engagement portion108′ and the sidewall portion 110′. The sidewall segment 110′ ispreferably linear with a positive slope such that the depth of gasketcavity 24 increases in the lateral to medial direction over the lengthof the sidewall segment 110′. The sidewall segment further preferablydefines a preferred angle α′ about twenty degrees (20°) with respect toa line parallel to the medial axis A′-A′. The sidewall segments 110′ arespaced about the medial axis A′-A′ to accommodate the thickness of thegasket 40.

The backwall portion of the inner surface profile 106′ of the housingcomponent 12′ preferably defines the deepest depth Hmax of the gasketcavity 24′, which is preferably about one-half inch (0.5 inch.) from abaseline B located in the plane of the pipe engagements surfaces 108′.In the complete coupling assembly 10, the backwall portion 112 definesthe maximum inner diameter of the coupling 10 which is preferably aboutseven inches (7 in.). The backwall portion 112 is preferably linearextending parallel to the coupling axis C-C to define the minimum widthof the cavity 24.

Extending between the sidewall portion 110′ and the backwall portion112′ is the transition portion 114′. The transition portion 114′preferably includes a first radiused portion 114′a contiguous with thesidewall portion 110′ and a second radiused portion 114″b contiguouswith the backwall portion 112. The transition portion 114′ includes apreferably linear segment 114′c that defines a narrowly tapering portionof the inner surface 22′ in the lateral to medial direction betweenpoints P′1 and P′2 to define a notch 30′ and a decreasing inner diameterover the segment 114 c′. Point P′1 is preferably located at the end ofthe sidewall portion 110′ and the concavely radiused portion 114′ahaving a preferred radius of curvature of under 0.1 inch and preferablyabout 0.06 inch. Point P2 is located at the end of the linear segment114′c and contiguous with a convexly radiused portion 114′d having aradius of curvature of under 0.1 inch and preferably about 0.06 inch.Moreover P1 is preferably located at a cavity depth h1 measured from thebaseline B, and P2 is preferably located at a cavity depth h2 from thebaseline B in which h2 is less than h1.

Shown in FIG. 4B is a preferred housing component 12″ for a preferrednominal two inch (2 in.) coupling 10″. The component has a first lateralside 100″ and a second lateral side 102″ spaced apart from one anotherto define the medial axis A″-A″ of the housing component 12″. Thelateral sides 100″, 102″ define the width W″ of the coupling 10″ aboutthe medial axis A″-A″ in which the width W″ preferably ranges from about1.5 to about 2 inch and is approximately 1.8 inch. The housing component12″ includes a peripheral surface 104″ which defines the outer surfaceof the coupling assembly 10. The housing component 12″ further includesan inner surface 106″ to define a gasket cavity 24″ for housing a gasket40. The preferred inner surface 106″ is symmetrical about the medialaxis A″-A″ and includes at the lateral side the pipe engaging surface108″. Extending medially, the inner surface 106″ further includes thesidewall portion 110″ with a substantially step transition 109″ betweenthe pipe engagement portion 108″ and the sidewall portion 110″. Thesidewall portion 110″ generally defines a positive slope such that thedepth of the gasket cavity 24″ increases in the lateral to medialdirection over the length of the sidewall segment 110′ to define apreferred angle α′ about thirty degrees and preferably abouttwenty-seven degrees (27°) with respect to a line parallel to the medialaxis A″-A″. The sidewall segments 110″ are spaced about the medial axisA″-A″ to accommodate the thickness of the gasket 40.

The backwall portion of the inner surface 106″ of the housing component12′ defines the deepest depth Hmax′ of the gasket cavity, which ispreferably about 0.5 inch from a baseline B″ that is located in theplane of the pipe engagements surfaces 108″. In the complete couplingassembly 10″, the backwall portion 112″ defines the maximum innerdiameter of the coupling 10″ which is preferably about three inches. Thebackwall portion 112 is preferably linear having a length extendingparallel to the coupling axis C-C to define a minimum width of cavity24. Extending between the sidewall portion 110″ and the backwall portion112″ is the transition portion 114″. The transition portion 114″preferably includes a first radiused portion 114″a contiguous with thesidewall portion 110″ and a second radiused portion 114″b contiguouswith the backwall portion 112″.

The transition portion 114″ includes a preferably linear segment 114″chaving a negative slope that defines a narrowly tapering portion of theinner surface 106″ in the lateral to medial direction between points P″1and P″2 to define notch 30″ and a decreasing inner diameter over thesegment 114 c″. Point P″1 is preferably located at the end of thesidewall portion 110′ and the concavely radiused portion 114″a having apreferred radius of curvature of under 0.1 inch and preferably about0.06 inch. Point P2 is located at the end of segment 114′c contiguouswith a convexly radiused portion 114′d having a preferred radius ofcurvature of under 0.1 inch and preferably about 0.06 inch. Moreover P″1is preferably located at a cavity depth h1 measured from the baselineB″, and P″2 is preferably located at a cavity depth h2 from the baselineB″ in which h2 is less than h1.

As previously noted, the notches 30 defined along the inner surfaces ofthe housing components 12 described above are configured to apply aradially inward compressive force against the gasket 40 to improveand/or maintain the fluid tight seal of the gasket 40. In particular,the notches 30 define a tapered or wedge surface along the inner surface22 of the coupling housing component 12 to apply a force to theperipheral surface of the gasket in a direction radially inward towardthe coupling center C-C and laterally outward toward the sidewallportions 110 of the housing 12. Gaskets 40 preferably for use with thecoupling housings described herein are annular or ring-type bodiesdefining a gasket center axis G-G for alignment with axis coupling C-C.

Shown in FIG. 5A is a preferred nominal six inch (6 in.) gasket 40 foruse with the preferred nominal six inch coupling 10′ of FIG. 4A. Thegasket annular body 42 has a first sidewall 44 for receiving the firstpipe segment 2, a second sidewall 46 for receiving the second pipesegment 14. The second sidewall 46 is spaced from the first sidewall 44to define a medial axis B-B therebetween that extends perpendicular tothe gasket central axis G-G. The annular body 42 includes an outerperipheral surface 48 and an inner surface 50 radially spaced from thegasket center axis G-G. Each of the peripheral and inner surfaces 48, 50are preferably symmetrical about the gasket medial axis B-B and aremoreover, preferably contiguous with the sidewalls 44, 46 of the gaskethaving radiused corner defining the transition between the sidewalls 44,46 and the peripheral and inner surfaces 48, 50 of the gasket.

In cross-section, the inner surface 50 defines a pair of sealing lipsurfaces 52 that are disposed preferably equilaterally about the medialaxis B-B. The sealing lip surfaces 52 directly engage the outer surfaceof the pipe segments to form a fluid tight seal upon application of asufficient compressive force about the gasket 40. The sealing lips 52define a profile that, in the uncompressed state of the gasket 40,defines an obtuse angle with a line parallel to the medial axis B-B theprofile sealing lips can include linear portions, radiused portionsand/or combination thereof. Preferably formed with and depending fromthe inner surface 50 along the medial axis is a central leg portion 54.The central leg acts as a buffer and divider between the ends of thepipe segments being joined together, as seen for example, in FIGS. 3Aand 3B. The profile of the preferred central leg 54 tapers narrowly inthe axial direction along the medial axis A′-A′ varying in thicknessover its axial length from about 0.1 inch to about 0.2 inch.

The inner surface 50 of the preferred gasket 40′ further includes atransitional segment 56 which connects the scaling lip surface 52 to thecentral leg 54. The transitional segment 56 defines a cavity or channel58 between the sealing lip surface and the central leg 54. The cavity 58defined by the transitional segment 56 provides a void into which thegasket body 42 can fold onto itself under the compressive forces of thehousing components 12, 14 of the coupling 10 and the fluid pressureconveyed in the pipe segments and through the pipe joint. Thetransitional segment 56 preferably includes a combination of radiusedportions and linear portions to connect the sealing lip surface 52 tothe central leg 54.

In the preferred embodiment of FIG. 5A, the transitional segment 56includes a first portion 56 a that preferably initiates with a firstconvexly radiused portion R1 that is contiguous with a linear segmentthat extends laterally toward the sidewall 44, 46 and peripherallytoward the peripheral surface 48 to a second radiused portion R2 aboutwhich the gasket body 42 folds. The transitional segment 56 furtherpreferably includes a second portion 56 b which is preferably initiallya line segment contiguous with the second radiused portion R2 andextends medially toward the medial axis A-A and toward the peripheralsurface 48 of the gasket to a preferably third radiused portion R3contiguous with the central leg 54. The preferred geometric profile andin particular the positively sloping segment 56 provide for a desirablegasket channel 58 in which the depth of the channel 58, as measured froma line parallel to the gasket axis C-C, increases in the lateral tomedial direction. Accordingly, the body 42 of the gasket 40 decreases inits radial thickness for at a portion of the body 42 over the lateral tomedial direction.

For the preferred gasket 40 of FIG. 5A the angled sidewall surfaces 44,46 are spaced apart to define a gasket thickness which ranges from aminimum thickness at the peripheral surface of about 0.9 inch to amaximum thickness of the entire gasket 40 of about 1.1 inches. Thepreferred gaskets are preferably dimensioned to slip on the ends of thepipe segments with at least a portion of the sealing lip surface 52forming a surface contact with the outer surface of the pipe segmentsand the central leg 54 engaging the end surface of the pipe segment. Fora nominal 6 inch pipe segment, the peripheral surface 48 defines apreferred outer diameter Dmax for the gasket 40 to be about seveninches. The central leg 54 defines a preferred minimum interior diameterDmin of the gasket of about 5.75 inches, and the sealing lips 52 definea preferred diameter D at its most medial end of about six inches. Thewidth of the central leg 54 preferably tapers in the radial directiontoward gasket axis G-G.

For the preferred inner surface 50 of the nominal 6 inch gasket, thethird radiused portion R3 includes a preferred radius of 0.06 inch andis located medially closer to axis B-B than R2. The second radiusedportion R2 includes a preferred radius of about 0.03 inch and is locatedcloser to the gasket axis G-G than the R3.

Shown in FIG. 5B is another preferred gasket 40′, which incorporatesimilar features of the previous embodiment, but is preferablydimensioned and configured for nominal two inch (2 in.) pipe segments.In particular, the peripheral surface of the gasket 40′ defines adiameter Dmax of about three inches, the central leg 54 defines apreferred minimum interior diameter Dmin of the gasket of slightly undertwo inches with the sealing lips 52 defining a preferred diameter D attheir most medial end of about two inches. For the preferred innersurface 50′ of the nominal 6 inch gasket, the third radiused portion R3′includes a preferred radius of 0.06 inch and is located medially closerto axis B′-B′ than R2′. The second radiused portion R2′ includes apreferred radius of under 0.1 inch and is located closer to the gasketaxis G-G than the R3′.

Referring again to FIG. 3B and the compressed state of the preferredcoupling arrangements 10, the low point P0 of the notch 30 of thehousing component is located medially inward of the a point P1 on thepreferred second radius R2 of the gasket 40 about which the gasketfolds. This preferred configuration provides for a surface contactbetween the inner surface 22 of the housing component 12 and theperipheral surface 48 of the gasket 40 which provides for a force havinga horizontal component in the lateral direction to improve or maintainthe contact between the sidewall portion 110 portion of the housingcomponent 12 and the sidewall 44, 46 of the gasket 40 in order tomaintain or increase the sealed engagement between the gasket and theouter surface of the pipe segments.

For each of the preferred gaskets 40′, 40″, the peripheral surface 48defines a profile that is substantially planar extending parallel to thecentral axis C-C of the gasket. In another alternative embodiment of thegasket 40″′, shown in FIG. 5C, the peripheral surface 48″′ defines aprofile that is non linear. In particular, the peripheral surface 48″′preferably defines a profile that is symmetrical about the medial axisof the gasket B″′-B″′ with two enlarged end portions 60″′ and a centralportion 62″′ located radially inward of the radiused end portions 60″′.In the embodiment of FIG. 5C the central portion 62″′ is preferablyarcuate and symmetrical about the medial axis B″′-B″′. The end portions60″′ provide a transition profile between the gasket sidewalls 44″′,46″′ and the central portion 62″′ of the peripheral surface. The profileof the end portion 60″′ can be defined by radiused segments,substantially linear segments or a combination of both. The surfaces ofthe end portions 60″′ alone or in combination with the central portion62″′ define a surface of the gasket that can engage the preferredtapered surface of the notch 30 in the coupling housing componentsdescribed herein to provide a normal force directed laterally in thedirection of the sidewall portion of the gasket housing. The diameter ofthe gasket 40″′ preferably varies from one lateral side of the gasket tothe next. Preferably, the radiused end portions 60″′ define a greaterdiameter of the gasket 40″′ than the central portion 62″′, and morepreferably the end portions 60″′ define the maximum diameter of thegasket 40″′ with the center of the arcuate portion 62″′ defining apercentage of the maximum gasket diameter ranging from about 90 percentto about 99 percent (90-99%). Accordingly, the gasket diameters definedat the end portions 60″′ and central portion 62″′ can define between oneanother a percent differential in the gasket diameter profile thatranges between one to about ten percent 1-10%). Alternatively, each ofthe end portions 60″′ and central portion″′ can define a perpendicularto the medial axis B″′-B″′ that further defines a radial differentialR_(D) along the medial axis B″′-B″′ that can be about 0.1 inch or less.

In view of the above descriptions of both the preferred gaskets andhousings, alternative pipe coupling arrangements are possible. Forexample, as shown in FIGS. 6A and 6B are schematic cross-sectionalillustrations of pipe coupling arrangements that use an alternateembodiment of the gasket 40″′. More specifically, shown in FIG. 6A is analternate embodiment of the gasket 40″′, the peripheral surface 48″′defines a profile having two enlarged end portions 60″′ with asubstantially linear central portion 62″′ therebetween that runssubstantially parallel to the gasket axis G-G and/or coupling axis X-X.In the arrangement of FIG. 6A, a housing 12 is provided having an innersurface 22 with a profile 106 that substantially mirrors the peripheralsurface 48″′ in a substantially dovetail fashion. More specifically, theinner surface 22 has an inner surface profile 106 in which the backwallportion 112 is preferably at the same cavity depth and contiguouslyformed with the notches 30 so as to define a centralized surface thatengages the substantially central linear portion 62″′ of the gasket 40″′in the assembled coupling arrangement. The backwall portion 112preferably engages the central linear portion 62″′ substantially alongits length. The inner surface profile 106 results in a pair of lateralrecesses symmetrically disposed about the backwall portion 112 forhousing the radiused end portions 60″′. In the embodiment of FIG. 6A,the notches 30 parallel and/or engage the substantially linear surfacesegments of the end portions 60″′ so as to provide the force in thelateral direction toward the sidewalls of the housing segment 12.

The preferred gaskets 40, 40′, 40″′ described herein can be used withhousing components that do not include notches 30. Accordingly, thepreferred gaskets 40, 40, 40″′ can be used with known housings. Theinventor has discovered a preferred radial differential R_(D) range asdefined between the enlarged end portions 60″′ and central portion 62″′of the gasket 40″′ for which a housing having a notch 30 is preferred.For a radial differential R_(D) of greater than 0.06 inch a notch isdesirable to provide the normal force having a laterally directedcomponent. For a radial differential R_(D) of about 0.06 inch or less,the coupling arrangement may employ a housing without a notch along theinner surface. For example, shown in FIG. 6B is the gasket 40″′ with ahousing 12 in which the inner surface 22 does not have a notch 30. Theenlarged end portions are configured to engage the housing inner surface22 such that in the assembled coupling configuration, the lateral walls44″′, 46″′ of the gasket 40″′ are directed laterally and the centralportion 62″′ is directed radially outward toward the backwall of thehousing. In the gasket 40″′, the profile of each enlarged end portion60″′ is preferably defined by a linear segment for engaging the housingbackwall with preferably radiused portions on each side that arerespectively contiguous with the central portion 48″′ and lateralsidewall of the gasket. The enlarged end portion 60″′ and centralportion 48″′ preferably define a radial differential R_(D) of about 0.06inch.

As noted above, the transitional segment 56″′ along the inner surface50″′ of the gasket can include a combination of varying radiusedportions and/or linear portions to connect the sealing lip surface 52 tothe central leg 54. For example, the transitional segment 56″′ canconsist of two or more radiused segment 56 a, 56 b, 56 c, 56 d extendingfrom the sealing lip surface 52″′ to the central leg 54″′ such that thechannel 58″ is substantially tear-dropped shaped. Alternatively, thetransitional segment 56″′ can include one or more linear segments asseen for example in FIGS. 6A and 6B. Moreover, the transitional segment56″′ can be configured so as to provide a desired average radialthickness of the gasket 40″′ so as to maintain a desired strength orresiliency in the gasket 40″′. Accordingly, the transitional segment56″′ and channel 58″′ can be configured such that the central portion48″′ and a tangential off the most radially outward portion of thechannel 58″′ perpendicular to the medial axis define a radial thicknessof the gasket being about 0.1 inch to about 0.175 inch.

Other aspects of the gaskets may be varied, such as for example as seenin FIG. 6B, the sealing lip surface 52″′ can include a combination ofradiused and/or linear segments to define a series of transition points52 a″′, 52 b″′, 52 c″′, and 52 d″′. The transition 52 d″′ preferablydefines a first inner diameter of the gasket that is greater than thenominal diameter of the pipe being joined. The transition 52 c″′ and 52b″′ preferably define respectively, the maximum and minimum pipediameter for the given nominal pipe diameter. The innermost transitionpoint 52 a″′ is radially located relative to the gasket center so as toprovide a sufficient seal about an outer pipe surface that may be out ofround for the given nominal pipe size. The preferred couplingarrangements described herein are preferably used to couple pipe ortubing and in particular copper or steel piping. The couplingarrangements of FIGS. 6A and 6B are well suited for joining steel pipeor tubing because the preferred sealing lip surfaces can effectivelyaddress large dimensional variations that may be experienced in joiningnominal sized steel piping. The preferred gaskets are preferablydimensioned to slip on the ends of the pipe segments with at least aportion of the sealing lip surface 52″′ forming a surface contact withthe outer surface of the pipe segments and the central leg 54″′ engagingthe end surface of the pipe segment. For a nominal four inch (4 in.)pipe segment, the peripheral surface 48″′ defines a preferred maximumouter diameter for the gasket 40″′ to be about five and a half inchesand more preferably 5.4 inches. The central leg 54″′ defines a preferredminimum interior diameter of the gasket of about four inches, and thesealing lips 52″′ define a preferred diameter at its most medial end ofabout four and a half inches and more preferably 4.4 inches. The widthof the central leg 54″′ preferably tapers in the radial direction towardgasket axis. For the preferred gasket 40″′ the angled sidewall surfaces44″′, 46″′ define an average thickness of about one inch and morepreferably a minimum thickness at the peripheral surface of about 0.9inches and a maximum thickness of the gasket 40″′ of about 1.2 inches.

Shown and described above are a preferred embodiments of nominal six,four and two inch coupling arrangements. The preferred arrangements canrange in size from a nominal one to twelve inch (1 in.-12 in.) coupling.Known gasket configurations may be used with the preferred housingcomponents 10 described herein. For example, as shown in FIGS. 9A and 9Bof U.S. Patent No. 61/255,351, standard style “C shaped” or “Tri-seal”gaskets as identified at page 12 in Tyco Fire & Suppression ProductsPublication IH-1000FP, entitled, “Grinnell®-Grooved Fire ProtectionInstallation Manual” (August 2007) can be used in the preferred couplingassemblies 10, 10′. A copy of page 12 from the installation manual isprovided in U.S. Patent No. U.S. Provisional Application No. 61/255,409,which is incorporated by reference in its entirety.

While the present invention has been disclosed with reference to certainembodiments, numerous modifications, alterations, and changes to thedescribed embodiments are possible without departing from the sphere andscope of the present invention. Accordingly, it is intended that thepresent invention not be limited to the described embodiments, but thatit has the full scope defined by the language of the following claims,and equivalents thereof.

What is claimed is:
 1. A coupling comprising: a housing having a firstlateral side for receiving a first pipe segment; a second lateral sidefor receiving a second pipe segment, the second lateral side beingspaced from the first lateral side to define a medial axis of thehousing; and an inner surface defining a cavity, the inner surfaceextending between the first lateral side and the second lateral side soas to be bisected by the medial axis and define an increasing depth ofthe cavity from each lateral side to the medial axis, the inner surfacehaving a sidewall portion and a backwall portion; and a gasket disposedin the housing for forming a seal about a pipe joint, the gasketincluding: a first lateral side; a second lateral side spaced from thefirst lateral side so as to define a medial axis therebetween; anexterior surface; and an inner surface, the exterior and inner surfacesextending between the first and second lateral sides so as to bebisected by the medial axis, the inner surface defining a central legextending along the medial axis, the inner surface further defining afirst sealing lip and a second sealing lip, the first and second sealinglips being disposed about the central leg so as to define a firsttransition portion of the inner surface extending between the firstsealing lip and the central leg and a second transition portion betweenthe second sealing lip and the central leg, the first and secondtransition portions extending in the direction from the respectivesealing lip towards the medial axis and the exterior surface, theexterior surface defining a profile having a pair of end portionsdisposed about the medial axis with a central portion extending betweenthe two end portions, the end portions defining the maximum diameter ofthe gasket, wherein in an assembled configuration, the inner surface ofthe housing engages the end portions to compress the gasket so as tofold the gasket about a point along the first and second transitionportions and direct at least one of the first and second lateral sidesof the gasket laterally against the sidewall portion of the innersurface of the housing.
 2. The coupling of claim 1, wherein in theassembled configuration the central portion of the peripheral surface isdirected outwardly toward the backwall of the housing.
 3. The couplingof claim 2, wherein in an uncompressed state the central portion is oneof substantially linear or substantially arcuate.
 4. The coupling ofclaim 1, wherein the end portions of the gasket are radiused.
 5. Thecoupling of claim 4, wherein the central portion of the gasket profileis radially inward of the end portions.
 6. The coupling of claim 1,wherein the inner surface of the gasket defines a central leg extendingalong the medial axis.
 7. The coupling of claim 1, wherein thetransition segment comprises at least one of a radiused portion and alinear portion.
 8. The coupling of claim 7, wherein the transitionsegment comprises a radiused portion defining a positive slope.
 9. Thecoupling of claim 7, wherein the transition segment comprises a linearportion defining a positive slope.
 10. The coupling of claim 1, whereinthe inner surface of the housing includes a first radiused portion, asecond radiused portion with a straight line segment extending betweenthe first and second radiused portions.
 11. The coupling of claim 10,wherein the first radiused portion has a center of curvature disposed onone side of the straight line, the second radiused portion having acenter of curvature disposed on the other side of the straight line, thefirst radiused portion defines a first cavity depth of the housing andthe second radiused portion defines a second cavity depth less than thefirst cavity depth.
 12. The coupling of claim 11, wherein the backwallportion defines a third cavity depth being any one of: (i) greater thanthe second cavity depth; (ii) less than at least the first cavity depth;or (iii) equal to the second cavity depth.
 13. The coupling of claim 12,wherein the cavity defines a central axis of the coupling, the backwallportion being substantially linear extending substantially parallel tothe central coupling axis.